This is a note to let you know that I've just added the patch titled
drm/i915/display: Fix an unsigned subtraction which can never be negative.
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
drm-i915-display-fix-an-unsigned-subtraction-which-c.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 3c4da8b02fdc672492ce796a91cd35ee20bed487
Author: Harshit Mogalapalli <harshit.m.mogalapalli@xxxxxxxxxx>
Date: Thu Dec 9 20:41:24 2021 -0800
drm/i915/display: Fix an unsigned subtraction which can never be negative.
[ Upstream commit 53b3495273282aa844c4613d19c3b30558c70c84 ]
smatch warning:
drivers/gpu/drm/i915/display/intel_dmc.c:601 parse_dmc_fw() warn:
unsigned 'fw->size - offset' is never less than zero
Firmware size is size_t and offset is u32. So the subtraction is
unsigned which can never be less than zero.
Fixes: 3d5928a168a9 ("drm/i915/xelpd: Pipe A DMC plugging")
Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@xxxxxxxxxx>
Reviewed-by: Lucas De Marchi <lucas.demarchi@xxxxxxxxx>
Signed-off-by: Lucas De Marchi <lucas.demarchi@xxxxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/20211210044129.12422-1-harshit.m.mogalapalli@xxxxxxxxxx
(cherry picked from commit 87bb2a410dcfb617b88e4695edf4beb6336dc314)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/gpu/drm/i915/display/intel_dmc.c b/drivers/gpu/drm/i915/display/intel_dmc.c
index b3c8e1c450efb..73076737add75 100644
--- a/drivers/gpu/drm/i915/display/intel_dmc.c
+++ b/drivers/gpu/drm/i915/display/intel_dmc.c
@@ -606,7 +606,7 @@ static void parse_dmc_fw(struct drm_i915_private *dev_priv,
continue;
offset = readcount + dmc->dmc_info[id].dmc_offset * 4;
- if (fw->size - offset < 0) {
+ if (offset > fw->size) {
drm_err(&dev_priv->drm, "Reading beyond the fw_size\n");
continue;
}
